Components with releasable leads and methods of making releasable leads

ABSTRACT

A connection component for a microelectronic device such as a semiconductor chip incorporates a support layer and conductive structures extending across a surface of the support layer. The conductive structures have anchors connecting them to the support layer, and releasable or unanchored portions.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a divisional of U.S. patentapplication Ser. No. 09/471,973, filed Dec. 23, 1999, which is acontinuation-in-part of U.S. Pat. No. 09/290,975, filed Apr. 13, 1999,which in turn is a continuation of U.S. Pat. No. 09/008,283, filed Jan.16, 1998 (now U.S. Pat. No. 5,904,498), which in turn is a Divisional ofU.S. Pat. No. 08/547,170, filed Oct. 24, 1995 (now U.S. Pat. No.5,763,941), the disclosures of which are all hereby incorporated byreference herein.

FIELD OF THE INVENTION

[0002] The present invention relates to a component useful in makingelectrical connections to microelectronic elements such as semiconductorchips, and to methods of manufacturing such components.

BACKGROUND OF THE INVENTION

[0003] Certain techniques for making semiconductor chip assemblies andsimilar microelectronic assemblies employ releasably attached leads. Onesuch process is disclosed in commonly assigned, U.S. Pat. No. 5,518,964,the disclosure of which is hereby incorporated by reference herein. Incertain preferred embodiments described in U.S. Pat. No. 5,518,964, afirst element such as a dielectric layer in a connection component isprovided with a plurality of elongated, flexible leads extending along asurface of the element. Each lead has a terminal end permanentlyattached to the first element and has a tip end offset from the terminalend. The tip ends of the leads may be releasably secured to the firstelement. A second element such as a semiconductor chip having contactsthereon is engaged with the first element or connection component, andthe tip ends of the leads are bonded to contacts on the chip or secondelement. The elements are then moved away from one another so as todeform the leads and provide vertically extensive leads extendingbetween the first and second elements, i.e., between the chip and theconnection component. A compliant material may be introduced between thechip and the connection component.

[0004] The resulting structure allows the chip to move relative to theconnection component without substantial stresses on the leads, and thusprovides compensation for thermal expansion. The preferred structurescan be readily tested and can be mounted on a further substrate such asa printed circuit panel or the like. Preferred embodiments of theprocesses disclosed in U.S. Pat. No. 5,518,964 can be used with chips orthe microelectronic element having large numbers of terminals. In thepreferred processes, many leads can be deformed simultaneously. Inparticularly preferred processes according to U.S. Pat. No. 5,518,964,the leads on a given connection component or first element may beconnected to contacts on a plurality of chips such as an array ofseveral chips or numerous chips formed as part of a wafer, so that manyleads are deformed simultaneously.

[0005] In certain embodiments disclosed in U.S. Pat. No. 5,518,964, thetip end of each lead is bonded to the surface of the first element by asmall spot of a base metal such as copper interposed between the tip endand the surface. Typically, such a spot is formed by a process in whichthe leads are formed from an etch-resistant metal such as gold overlyinga continuous layer of the base metal. The leads have wide portions atthe tip and terminal ends. The component is then subjected to an etchingprocess so as to undercut the lead and remove the base metal frombeneath the etch-resistant metal at all locations except at the terminalend and at the tip end. At the tip end, most, but not all of the basemetal is removed from beneath the etch-resistant metal, leaving a verysmall spot of the base metal. The strength of the bond between the tipand the connection component surface is effectively controlled by thesize of the spot. Thus, although the base metal may provide a relativelyhigh bond strength per unit area or per unit length, it may stillprovide a weak attachment. Although structures such as frangible leadsections and small buttons can provide useful releasable attachments forthe tip ends of the leads, some care is required in fabrication to formthese features. For example, formation of spots of uniform size beneaththe terminal ends of leads on a large connection component requirescareful control of the etching process.

[0006] As described in PCT International Publication WO 94/03036, thedisclosure of which is hereby also incorporated herein by reference, aconnection component may incorporate a support structure such as apolyimide or other dielectric layer with one or more gaps extendingthrough such layer. Preferably, the support structure incorporates oneor more flexible or compliant layers. The connection component mayfurther include leads extending across the gap. Each lead has a first orterminal end permanently secured to the support structure on one side ofthe gap, and a second end releasably attached to the support structureon the opposite side of the gap. In preferred processes as taught by'036 publication, the connection component is positioned on asemiconductor chip or other microelectronic element. Each lead isengaged by a bonding tool and forced downwardly into the gap, therebydetaching the releasably connected second end from the supportstructure. The leads are flexed downwardly into the gap and bonded tothe contacts on the chip or the microelectronic element. Preferredconnection components and processes according to the '036 publicationalso provide highly efficient bonding processes and very compactassemblies. The finished products provide numerous advantages such ascompensation for thermal expansion, ease of testing and a compactconfiguration.

[0007] Other structures disclosed in the '036 publication and in U.S.Pat. No. 5,518,964 employ frangible lead sections connecting thereleasable end of each lead to another structure permanently mounted tothe support structure or first element. Frangible sections can alsoprovide useful results. However, such frangible elements are mostcommonly formed by using the photo-etching or selective depositionprocesses used to form the lead itself to form a narrow section. Theminimum width at the narrow section, can be no less than the smallestwidth formable in the process. As the other portions of the leadadjacent the narrow section must be wider than the narrow section, theseother portions must be larger than the minimum attainable in theprocess. Stated another way, the leads made by such a process generallyare wider than the minimum line width attainable in the formationprocess. This limits the number of leads which can be accommodated in agiven area.

[0008] In other embodiments disclosed in the '036 publication, the firstor permanently mounted terminal end of a lead may have a relativelylarge area, whereas the second or releasably mounted end of the leadoverlying the support structure may have a relatively small area, sothat such second end will break away from the support structure beforethe first end when the lead is forced downwardly by the bonding tool.This arrangement requires careful control of the dimensions of the endsto control the area of the bond between the lead end and the supportstructure and also requires a lead wider than the smallest elementformable in the process.

[0009] As described in the '036 publication, and as further described incommonly assigned International Publication WO 97/11588, the disclosureof which is also incorporated by reference herein, leads used in theseand other microelectronic connection components may include polymericlayers in addition to metallic layers. The polymeric layers structurallyreinforce the leads. For example, certain leads described in the '588publication incorporate a pair of thin conductive layers such asmetallic layers overlying opposite surfaces of a polymeric layer. Oneconductive layer may be used as a signal conductor, whereas the oppositeconductive layer may act as a potential reference conductor. Thecomposite lead thus provides a stripline extending along the lead. Astripline lead of this nature can provide a low, well-controlledimpedance along the lead, which enhances the speed of operation of thecircuit formed by the connection component and the associatedmicroelectronic elements. The potential reference conductor also helpsto reduce crosstalk or undesirable inductive signal coupling betweenadjacent leads.

[0010] In certain embodiments disclosed by commonly assigned U.S. patentapplication Ser. No. 09/020,750, filed Feb. 9, 1998, the disclosure ofwhich is hereby incorporated by reference herein, a starting structurehas one or more metallic leads overlying a polymeric dielectric layer.The dielectric layer is exposed to an etchant for etching the dielectriclayer. The etchant attacks the dielectric layer so that the leads arereleasably attached to the dielectric layer by connection regions of thedielectric layer which remain after the etching step.

[0011] Another method of making connection components with releasableleads is disclosed in certain embodiments of U.S. patent applicationSer. No. 09/200,100, filed Nov. 25, 1998, the disclosure of which ishereby incorporated by reference herein.

[0012] Accordingly, further improvements in releasable lead structuresand methods of making the same are desired.

SUMMARY OF THE INVENTION

[0013] A method in accordance with one aspect of the present inventioncomprises a method of making a connection component comprising the stepsof providing a starting structure including one or more metallicconductive structures overlying a surface of a support layer. The areaof contact between the surface of the support layer and the conductivestructures is reduced by removing material from the one or moreconductive structures or the support layer or both so as to leave aplurality of etch-defined anchors connecting the one or more conductivestructures to the support layer and at least some portions of theconductive structures unattached or releasably attached to the supportlayer. The plurality of anchors are spaced from one another on the oneor more conductive structures. According to this aspect of the presentinvention, the anchors attach the conductive structures to the supportstructure and support the conductive structures thereon. The anchors arespaced along the conductive structures and may comprise segments of thesupport layer or the conductive structures. The conductive structureshave sections sufficiently wide to form the anchors for supporting theconductive structures on the support structure.

[0014] Connection components typically include terminals which may bespaced on the surface area of the connection component. In formingconductive structures on a component, conductive structures span adistance along a surface of the connection component to form connectionswith the terminals. In some cases, routing the conductive structures onthe component requires conductive structures which are relatively longerthan others. Releasable conductive structures may be long enough tobecome vulnerable to unwanted detachment from the connection component.It is desirable that the conductive structures include some sectionsbeing wide enough to form a secure connection with the component andsome sections being narrow enough to closely space the conductivestructures on the component.

[0015] Thus, the conductive structures most preferably include widersections and narrow elongated sections extending between the widersections. The removing material step is performed so that the anchorsextend from the wider sections to the support layer. The narrowelongated sections enable the conductive structures to be closely spacedon the connection component while the conductive structures aresupported at the wider sections. The one or more conductive structurespreferably comprise a plurality of conductive structures.

[0016] A method in accordance with the invention preferably includes astep of removing material by etching the conductive structures byexposing the conductive structures to an etchant. The support layer, incertain preferred embodiments, includes a layer of dielectric material.The support layer preferably comprises a material relatively unaffectedby the step of etching the conductive structures. In other preferredembodiments, the support layer comprises a layer of a metallic materialhaving different etching properties from the conductive structures.

[0017] In certain preferred embodiments, the support layer comprises alayer of dielectric material and the step of removing material comprisesetching the support layer by exposing the support layer to an etchant.

[0018] In other preferred embodiments, the support layer includes alayer of metallic material having different etching properties from themetallic material of the conductive structures and the step of removingmaterial comprises etching the layer of metallic material by exposingthe layer of metallic material to an etchant.

[0019] The step of reducing the area of contact between the supportlayer and the conductive structures may be performed so as to leave atleast one elongated lead portion of the conductive structures. The stepof reducing the area of contact may be performed so as to leave at leastone portion of the conductive structures unattached to the supportlayer. However, the step of reducing the area of contact may also beperformed so as to leave at least one portion of the conductivestructures releasably attached to the support layer. Thus, theconductive structures. The step of reducing the area of contact mayinclude portions which are unattached to the support layer and/orportions which are releasably attached to the support layer.

[0020] The conductive structures may include a base layer and a coverlayer overlying the base layer. The step of etching the conductivestructures may be performed so as to remove metal from the base layer,undercutting the conductive structures, tending to reduce the area ofcontact between the support layer and the conductive structures. Theconductive structures may include an etching mask covering a portion ofthe conductive structures during the step of etching the conductivestructures. The cover layer may comprise a metal different from the baselayer of the conductive structures so that the cover layer remainssubstantially unaffected by the step of etching.

[0021] The conductive structures preferably have sections of differentwidths, as discussed briefly above. In certain preferred embodiments,the conductive structures include a plurality of wider sections having afirst width and at least one narrower section having a second widthsmaller than the first width. During the step of removing material, theanchors are formed at the wider sections and the at least one portionunattached or releasably attached is formed at the at least one narrowersection. The at least one narrower section may comprise an elongatedportion of the conductive structures. The at least one narrower sectionmay also include a section extending across a gap in the support layerwhich is movable with respect to the support layer. In this aspect ofthe invention, the conductive structures may comprise leads which may beforced downwardly through the gap to be bonded to a microchip or othermicroelectronic element, such as a wafer disposed beneath the connectioncomponent. A segment of the lead which is releasably attached to thesupport layer is detached from the support layer during the forcing ofthe lead downwardly through the gap, as discussed in certain embodimentsof PCT International Publication No. WO 94/03036, the disclosure ofwhich is hereby incorporated by reference herein.

[0022] The conductive structures may overlie a first surface of thesupport layer so that the step of reducing the area of contact includesthe step of exposing the first surface to an etchant. The step ofetching the support layer may comprise utilizing a gaseous etchant,which may include one or more oxidizing species, or a plasma of areaction gas including one or more oxidizing gases with or without oneor more carrier gases. Material may be removed from the support layer orthe conductive structures or both utilizing a chemical etchant such asHCl or CuCl.

[0023] The method of making a connection component in another aspect ofthe invention comprises providing a starting structure including one ormore metallic conductive structures overlying a surface of the supportlayer and removing material from the one or more conductive structures,the support layer or both so as to leave at least one elongatedetch-defined anchors connecting the one or more conductive structures tothe support layer and at least some portions of the conductivestructures releasably attached to the support layer. Methods inaccordance with this aspect of the invention may otherwise be performedas discussed above. Each of the conductive structures preferably has awider section having a first width and a narrower section having asecond width smaller than the first width so that during the step ofremoving material, an anchor is formed from the wider section. Anunattached or releasably attached portion is formed from the narrowersection.

[0024] In another aspect of the present invention, a microelectronicconnection component comprises a support structure including a supportlayer having a surface and one or more metallic conductive structuresoverlying the surface of the support layer, and a plurality of anchorsspaced from one another and attaching the conductive structures to thesupport layer at an anchored portion. The plurality of anchors have anarea of contact with the one or more conductive structures which is lessthan the area of the conductive structures at the anchored portion. Incertain preferred embodiments, the anchors are integral with theconductive structures. In other preferred embodiments, the anchors areintegral with the support layer. The conductive structures, in certainpreferred embodiments, include releasable connections between theconductive structures and the support layer. In other preferredembodiments, the conductive structures include portions unattached tothe support layer.

[0025] The conductive structures preferably include elongated portionsand anchors at anchored portions of the conductive structures, theanchors having a width larger than releasable portions of the conductivestructures. The conductive structures, in certain preferred embodiments,preferably include releasable portions extending across a gap in thesupport layer, as discussed above. The elongated releasable portions maybe curved. The curvature of the releasable segments provides additionallength for spanning between the connection component and a microchip orother microelectronic elements, such as wafers.

[0026] The conductive structures may include portions vertically spacedfrom the support layer. The conductive structures, in preferredembodiments, are spaced on the component so that wider portions of afirst conductive structure are adjacent narrower portions of a secondconductive structure.

[0027] In other preferred embodiments, the microelectronic connectioncomponent comprises a support structure including a support layer havinga surface and one or more metallic conductive structures overlying thesurface of the support layer, the conductive structures being verticallyspaced from the surface by at least one elongated anchor attaching theconductive structures to the support layer. The anchors may be integralwith the conductive structures of the support layer. In certainpreferred embodiments, the conductive structures include releasableconnections between the conductive structures and the support layer. Inother preferred embodiments, the conductive structures include portionsunattached to the support layer.

[0028] The conductive structures, in preferred embodiments, includesections with a first width and narrower sections having a second widthsmaller than the first width, the wider sections being attached to thesupport layer by the at least one anchor. The conductive structures mayinclude elongated narrower sections extending across a gap in thesupport layer, in certain preferred embodiments. The elongated narrowersections may be curved.

[0029] These and other objects, features and advantages of the presentinvention will be more readily apparent from the detailed description ofthe preferred embodiment, taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030]FIG. 1 is a partial top right perspective view of a startingstructure for a method in accordance with one embodiment of theinvention;

[0031]FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1;

[0032]FIG. 3 is the cross-sectional view of FIG. 2 at a later time inthe method;

[0033]FIG. 4 is the cross-sectional view of FIGS. 2-3 at a later time inthe method;

[0034]FIG. 5 is a top right perspective view of FIG. 3;

[0035]FIG. 6 is a partial plan view of a connection component made inaccordance with the embodiment of FIGS. 1-5;

[0036]FIG. 7 is a cross-sectional view similar to FIG. 2, in a method inaccordance with a further embodiment of the invention;

[0037]FIG. 8 is the cross-sectional view of FIG. 7 at a later time inthe method;

[0038]FIG. 9 is a top right perspective view of a connection componentmade in a method in accordance with a further embodiment of theinvention;

[0039]FIG. 10 is a partial top plan view of a connection component madein a method in accordance with another embodiment of the invention;

[0040]FIG. 11 is a partial top right perspective view of a connectioncomponent made in accordance with a further embodiment of the invention;

[0041]FIG. 12 is a cross-sectional view taken along line 12-12 in FIG.11; and

[0042]FIG. 13 is a top right perspective view of a connection componentin accordance with a further embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] A process in accordance with one embodiment of the inventionincludes providing a starting structure 11, including a support layer 12comprising a layer of dielectric material commonly used in electroniccomponents, such as polyimide having a number of conductive structuressuch as traces 13 extending along a first surface 14 of the supportlayer 12. The traces 13 have a number of elongated sections 15 and anumber of wider sections or buttons 16 distributed along the length ofthe traces 13 so that the elongated sections 15 extend between thebuttons 16. The elongated sections 15 have a width W1 which is smallerthan the width W2 of the buttons 16, as shown in FIG. 1. The traces 13have a narrow lead section 18 at an end 20 of each trace 13. Narrow leadsection 18 also has a width less than the width W2. In certain preferredembodiments, the narrow section 18 curves in a direction transverse tothe length of the traces 13.

[0044] The starting structure 11 may be formed in a number ofconventional processes. Traces 13, for example, may be formed bydepositing electrically conductive metal onto the support layer 12 inthe pattern of the traces 13 by plating metal in a pattern defined by aphotographically patterned mask. A metal layer may be laminated onto thesupport layer 12 and the metal layer may be etched in a pattern definedby a patterned mask. A number of other conventional processes may alsobe utilized. Processes for forming traces which provide strong adhesionbetween the traces and the support layer are preferred. The traces 13may be formed from virtually any electrically conductive metal and mayinclude layers of different metals. The starting structure may comprisea structure including a number of dielectric layers having layers ofinternal conductive elements. The starting structure may be fabricatedas disclosed in commonly assigned U.S. patent application Ser. No.09/020,750, filed Feb. 9, 1998, the disclosure of which is herebyincorporated by reference herein.

[0045] As shown in FIGS. 2-5, the starting structure starts off with thetraces 13 firmly attached to layer 12. First surface 14 of support layer12 is subjected to an etchant which etches away the first surface 14around the traces 13. A mask of material resistant to the etchant may beutilized to protect the other surfaces of the support layer from theetchant. As the etchant progressively removes material from the supportlayer 12, the etchant erodes the first surface 14 of the support layerso that the first surface recedes. The etchant then progressivelyremoves material from the support layer 12 underneath the traces 13. Asshown in FIG. 3, the newly created first surface 14 has receded from thetrace 13 so that the trace is vertically spaced from the support layer12. However, the etching is halted before all of the dielectric materialunderneath buttons 16 has been removed, leaving anchors 25. The anchorscover a sufficient area of the traces 13 to firmly connect traces 13 tothe support layer 12. Thus, the traces 13 have anchored portions 26 andunanchored portions 27.

[0046] The anchors 25 have an area of contact 25A with the trace 13. Thearea of contact 25A is less than the surface area 16A of the trace 13 atthe buttons 16, as seen in FIG. 5.

[0047] After forming anchored and unanchored portions for the traces 13in the component 10, the traces 13 may be bonded to contacts 29 on amicrochip or other microelectronic device 28 as shown in FIG. 4. In onemethod of connecting the component, an end 20 of narrow lead section 18is bonded to contact 29 and support layer 12 and microelectronic element28 are moved in relation to each other to deform narrow lead section 18and provide a space between the support layer 12 and microelectronicelement 28. An encapsulant, which may be a rigid encapsulant butpreferably comprises a compliant material, can be used to encapsulatethe assembly. Injection of an encapsulant may also be utilized so thatthe microelectronic element 28 and the support layer 12 may are movedapart from each other to create space for the encapsulant. The assemblyof microelectronic element 28 and the support layer 12 may eaccomplished as disclosed in certain embodiments of U.S. Pat. No.5,518,964, the disclosure of which is hereby incorporated by referenceherein.

[0048] A preferred method of etching support layer 12 is to expose thesupport layer to a gaseous etchant which desirably is a plasma ofoxidizing reactant gas mixture incorporating one or more oxidizingmoieties such as a halogen, oxygen, or mixtures thereof, as disclosed inU.S. patent application Ser. No. 09/020,750, filed Feb. 9, 1998, thedisclosure of which is hereby incorporated by reference herein.

[0049] The resulting connection component has a support structure 19including a support layer 12, and a number of metallic conductivestructures 13 overlying a surface of the support layer 12. Theconductive structures 13 are vertically spaced from the first surface 14of the support layer 12 by a plurality of anchors 25 extending betweenthe conductive structures 13 and the support layer 12. The anchors 25extend from a wider section 16 of conductive structures 13 to the firstsurface 14 of the support layer 12. Elongated sections 15 extend betweenthe wider sections 16. The anchors 25 are spaced along the length of theconductive structures 13 so that elongated sections 15 are unsupportedand extend above the first surface 14 of the support layer 12.

[0050] Traces formed in accordance with the foregoing embodiment of theinvention may be closely spaced on a connection component, asillustrated in FIG. 6. The narrower elongated sections 15 enable thetraces 13 to be closely spaced adjacent one another on the support layer12 and the wider sections 16 are staggered and positioned adjacent theelongated sections 15 for this purpose.

[0051] In a method in accordance with another embodiment of theinvention, shown in FIGS. 7 and 8, a starting structure 111 has asupport layer 112 formed from a dielectric material such as polyimide,and metallic conductive structures comprising a number of traces 113extending on a surface of the support layer 112, as discussed above inconnection with FIG. 1. In this embodiment, traces 113 are comprised ofa base layer 129 of metal in contact with the support layer 112 and acover layer 130 of a different metal, having different etchingproperties from the metal of the base layer, overlying the base layer129. For example, the base layer may be comprised of copper or acopper-rich alloy and the cover layer 130 may be comprised of anetch-resistant metal such as gold. Acid etching solutions such as HCland CuCl may be used. During the etching process, a liquid etch solutionattacks the base layer 129, undercutting the trace, and progressivelyseparating the trace 113 from the support layer 112. The etchant,however, leaves the support layer substantially unaffected. The baselayer may be etched as discussed in connection with certain embodimentsof U.S. Pat. No. 5,518,964, the disclosure of which is herebyincorporated by reference herein. After the step of removing metal, thetraces 113 are vertically spaced from the support structure 112, asshown in FIG. 8. An end 120 of the trace 113 in the resulting component110 may comprise a lead section 118 for connection to a microchip oranother microelectronic element, such as a wafer as discussed above inconnection with FIG. 4.

[0052] Thus, material may be removed from the metallic conductivestructures or the support layer or both to separate the conductivestructures from the support layer while creating anchors which firmlyattach the conductive structures to the support layer. The removing ofmaterial may be performed by etching where the support layer and metalor metals of the conductive elements have different etchingcharacteristics. Alternatively or additionally, etch-resistant masks maybe utilized to protect the support layer, the conductive structures, orportions thereof, from the etchant utilized. After etching, the mask maybe rinsed away from the component. The support layer may comprise alayer of any polymeric dielectric or metallic material having thedesired characteristics, as discussed above. The conductive structuresmay be comprised of any electrically conductive material having thedesired characteristics as discussed above. The support layer may alsoinclude a layer of metal having different characteristics from theconductive structures, as shown in FIG. 9. For example, the supportlayer 219 may be comprised of top layer 212A of aluminum or an aluminumalloy overlying a bottom layer of 212B of dielectric material. Thealuminum or aluminum alloy is etchable in a caustic etch solution. Thealuminum layer is etched, leaving anchors like those shown in FIG. 3 andtraces 213, which may be comprised of copper. The support layer 212 mayinclude a metal unaffected by an etching solution which attacks themetal of the traces or other conductive structures 213.

[0053] Methods in accordance with the present invention may form anchorsin various configurations. In a method according to a further embodimentof the invention, an elongated anchored portion 326 as shown in FIG. 10is formed. The starting structure in this embodiment comprises a supportlayer having a number of traces 313 extending on a surface thereof. Thetraces have a wider section for forming an anchor 325 securely attachingthe traces 313 to the polyimide support layer 312. The traces 313 alsoinclude a narrower section for forming unanchored portions 327. Theanchored portions 326 and unanchored portions 327 are formed in anetching process which removes material from the traces or the supportlayer 312 or both, as discussed above.

[0054] The microelectronic connection component formed includeselongated anchors 325 attaching traces 313 to a support layer 312 asshown in FIG. 10. The traces 313 also include unanchored section 327 forbonding to a microchip or other microelectronic element, such as awafer, as discussed above.

[0055] In a method according to another embodiment of the invention, theetching process is halted before portions of the traces are entirelydetached from the support layer. As shown in FIGS. 11 and 12, thesupport layer 412 is subjected to an etching process which removesmaterial from the support layer beneath the traces 413. The etchingprocess is continued until only narrow, web-like elements 417 remainbeneath elongated sections 415 of the traces 413. The material beneathwider sections 416 remain as anchors 425 firmly connecting traces 413 tothe support layer 412. Thus, a releasable lead portion 428 of the traces413 may be formed. Web-like elements 417 are narrow enough to releasablyattach lead portions 428 to the support layer 412 so that an end 420 oflead portion 428 may be bonded to a microchip or other microelectronicelement, such as a wafer, and deformed in the manner discussed above.During the deformation of the lead portion 428, the web-like element 417is broken so that lead portion 428 may be displaced with respect to theremainder of the trace 413.

[0056] The connection components of FIGS. 11 and FIG. 5 may include areleasable lead portion 428 as shown in FIG. 11 or an unanchored portion27 as shown in FIG. 5 for bonding to a microchip or othermicroelectronic element, such as a wafer, as discussed above. Thereleasable portion and the unanchored portion are preferably curved in adirection transverse to the length of the trace to provide a sufficientlength for spanning a space between the connection component and themicrochip or other microelectronic element.

[0057] A connection component in accordance with another embodiment ofthe invention is shown in FIGS. 11 and 12. The connection component issimilar to the one illustrated in FIG. 5 but includes web-like elements417 extending from the elongated sections 415 to the support layer 412and extending between anchors 425. The web-like elements 417 aresignificantly narrower than the anchors 425. The elongated sections andweb-like elements may be formed from the same material as the supportlayer 412 or from material which previously extended on support layer412, such as metallic portions of the traces 413, which was removed in asubtractive process as discussed above. Web-like narrow portions of thebase metal 129 in FIG. 7 may remain connecting the traces 113 to supportlayer 112.

[0058] In another method in accordance with a further embodiment of theinvention is shown in FIG. 13. Lead portions 527 of traces 513 may beprovided on a starting structure having a gap 521 so that the leadportions 528 extend across the gap 521. A lead portion 528 extendsacross the gap 521, whereas portions of the traces 513 are firmlyattached to the support layer 512 by anchors 525 formed in one of themethods discussed above. The structure may be assembled with a microchipor other microelectronic element and the unanchored or releasable leadportion may be connected to the microchip or other microelectronicelement as discussed in connection with certain embodiments of U.S. Pat.Nos. 5,904,498 and 5,763,941 and PCT International Publication No. WO94/03036, the disclosures of which are hereby incorporated by referenceherein.

[0059] As these and other variations and combinations of the featuresdiscussed above can be utilized without departing from the presentinvention, the foregoing description of the preferred embodiment betaken by way of illustration rather than by way of limitation of theinvention as defined by the claims.

1. A microelectronic connection component comprising: (a) a supportstructure including a support layer having a surface; (b) one or moremetallic conductive structures overlying said surface of said supportlayer; (c) a plurality of anchors spaced from one another and attachingthe one or more conductive structures to the support layer at ananchored portion of the one or more conductive structures, saidplurality of anchors having an area of contact with the one or moreconductive structures, said area of contact being less than the area ofthe conductive structures at said anchored portion.
 2. The component ofclaim 1 , wherein said anchors are integral with said conductivestructures.
 3. The connection component of claim 1 wherein said anchorsare integral with said support layer.
 4. The component of claim 1further comprising releasable connections between said conductivestructures and said support layer.
 5. The component of claim 1 whereinsaid conductive structures include portions unattached to said supportlayer.
 6. The component of claim 1 wherein said conductive structuresinclude elongated portions and said anchored portions have a widthlarger than said elongated portions.
 7. The component of claim 1 whereinsaid conductive structures include releasable portions releasablyattached to said support layer.
 8. The component of claim 1 wherein saidconductive structures include elongated releasable portions extendingacross a gap in said support layer.
 9. The component of claim 8 whereinsaid elongated releasable portions are curved.
 10. The component ofclaim 1 wherein said conductive structures include portions verticallyspaced from said support layer.
 11. The component of claim 1 whereinsaid conductive structures include sections of different widths,including a plurality of wider sections having a first width and aplurality of narrower sections having a second width less than saidfirst width, said anchors attaching the conductive structures to saidsupport layer at said wider sections.
 12. The component of claim 11wherein said conductive structures are spaced on said component so thatsaid wider portions of a first conductive structure are adjacentnarrower portions of a second conductive structure.